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ARS Home » Plains Area » Fargo, North Dakota » Edward T. Schafer Agricultural Research Center » Cereal Crops Improvement Research » Research » Publications at this Location » Publication #424297
Research Project: Improvement of Disease and Pest Resistance in Barley, Durum, Oat, and Wheat Using Genetics and Genomics

Location: Cereal Crops Improvement Research

Title: Genetic characterization and confirmation of stem rust resistance (Sr) genes in Rusty-derived durum monogenic lines

Author
item Klindworth, Daryl
item Fiedler, Jason
item Jin, Yue
item Friesen, Timothy
item Anderson, Kirk
item Lhamo, Dhondup
item Xu, Steven
item Peters Haugrud, Amanda

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/8/2025
Publication Date: 8/10/2025
Citation: Klindworth, D.L., Fiedler, J.D., Jin, Y., Friesen, T.L., Anderson, K.M., Lhamo, D., Xu, S.S., Peters Haugrud, A.R. 2025. Genetic characterization and confirmation of stem rust resistance (Sr) genes in Rusty-derived durum monogenic lines. Crop Science. 65(4). https://doi.org/10.1002/csc2.70134.
DOI: https://doi.org/10.1002/csc2.70134

Interpretive Summary: Stem rust is one of the most destructive diseases of durum wheat. Important genes for stem rust resistance were transferred to durum wheat from genetic stocks during the mid-20th century. We examined six lines carrying a unique stem rust gene derived from these four parents. The genes in these lines have been characterized and their identities have been postulated from disease resistance tests. But since postulations can be incorrect, our objective was to use genetic tests to confirm the postulations. The genetic tests confirmed that the genes in five of the six lines were correctly postulated. The sixth gene was determined to be incorrectly postulated and therefore reassigned. While none of the genes in this study provide resistance to all of the highly virulent races presently found in Africa, multiple of the genes identified provide resistance to either a limited number of highly virulent races or may be useful in limit circumstances. Therefore, these lines should be useful either for plant breeding or useful to study the interaction of plant genetics and disease resistance.

Technical Abstract: Improved genetic stocks carrying stem rust resistance (Sr) genes are important tools for combating stem rust caused by the rust pathogen Puccinia graminis Pers. f. sp. tritici Eriks and E. Henn in durum wheat (Triticum turgidum L. subsp. durum (Desf.) Husn) and common wheat (T. aestivum). Several tetraploid wheat lines, namely Vernal, Khapli, CItr8155, and ST464, were important sources of Sr genes in durum cultivars in the mid-20th century. These four lines were used to transfer six Sr genes to a near-isogenic Rusty background. The Sr genes in the six monogenic lines have been postulated, but genetic studies have not been conducted to confirm the postulations. In the present study, we used race specificity tests, gene mapping, haplotyping, and sequencing to confirm postulations. Genetic testing confirmed five of the six gene postulations. Rusty-ST464A1 had been postulated to carry Sr8b but based on race specificity testing and haplotyping with IWB10588, we concluded that monogenic lines Rusty-8155B1 and Rusty-ST464A1 both carried Sr8155B1. Gene sequencing was used to identify Sr9e haplotypes and based on this test we determined that Rusty-ST464A2 and Rusty-VnB1 carried Sr9e_h1 and Sr9e_h2, respectively. Gene mapping located the Sr gene in Rusty-KLA to the distal region of 4AL. Based on the map-location and race specificity, we concluded Rusty-KLA carries Sr7a. Gene mapping located the gene in Rusty-KLD to chromosome 1B. Based on this location and race specificity testing we concluded that the gene in Rusty-KLD was Sr14. Markers linked to Sr14 will be useful in subsequent studies including gene sequencing.